Optical fiber as used in standard telecommunications and other applications is based upon the principle of snell's law and total internal reflection. Each fiber has a central core and an outer layer known as the cladding. By establishing a core with an index of refraction higher than the index of refraction of the cladding, the light will totally reflect internally rather than passing through the core and become lost.
The employment of a device known as a ferrule makes optical fiber connectors possible. This device supports and aligns the optical fiber or fibers, allowing for a precise coupling of fibers. In a single fiber connector, the ferrule is generally a cylindrical structure, and is often ceramic. The ferrule holds the fiber in a central portion thereof and is adhered therein with cured epoxy resin. Polishing the end of the fiber in the ferrule creates an optically smooth, planar surface with the optical fiber aligned as close as possible to the center of the ferrule. When two unstable ferrules are aligned end to end through a mechanical connector, optical coupling takes place allowing the optical transfer therethrough. However, the joining ferrule surfaces may not be orthogonal, thus producing unwanted reflection.
Backplanes (circuit boards known in the art as motherboards), which support a plurality of secondary circuit boards (known in the prior art as “daughterboards”) are well known. The daughterboards are connected to the backplane through connectors which not only serve to mechanically grip the daughterboards, but also provide an electrical connection between each daughterboard and the backplane.
There is a need in the art for an improved optical backplane which permits daughterboards to be optically and electrically connected thereto. It is to such an improved optical backplane and components for constructing the backplane assembly that the present invention is directed.